1. Technical Field
The present invention relates to systems and methods for active peak power management. More particularly, some embodiments disclosed herein relate to peak power management for a high performance embedded microprocessor cluster.
2. Description of the Related Art
Power supplies for handheld embedded systems typically are a tradeoff between cost, form factor, and sustainable current at the highest expected performance level. This allows for a price-optimized design while sustaining everyday performance requirements of the system.
However, some applications and/or specifically designed tests could be capable of exceeding the design limits and the system is required to regulate the performance of the microprocessor cluster to stay within the sustainable supply envelope.
To achieve peak performance for a limited duration and buffer current inrush events, chip package and board level capacitors are employed. These deliver peak current before the power supply regulation can catch up with demand. With each peak performance event, the power supply will recharge these system capacitors, adding to the base load of the power supply. If the power supply cannot meet this demand, the system experiences a voltage drop. To avoid failure of the system, operating margins for voltage and frequency of the processor system are added.
This arms race between CPU power requirements and power supply stiffness adds to the bill of materials without contributing to the average system performance. Reducing peak power without increasing the power supply capability and system operating margins has been achieved so far through: predictive power estimation at dispatch time of power intensive instructions and controlling of the dispatch rate for the power intensive instructions based on the predictions; and voltage drop sensor employment at CPU core supply lines for ad-hock dispatch rate reduction or clock dithering based on in flight instructions. Such methods improve the system, but do not influence the ratio between active decoupling capacitance and power supply stiffness. Hence, the power supply is still required to recharge all peak discharge capacitance on time to prevent a significant voltage drop.
Therefore a system including at least a power management unit and/or a method which actively moderates peak power demands would be highly desirable.